Excretion of endogenous and exogenous purine derivatives in sheep: effect of increased concentrate intake

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1998Suggested citation
Pérez, J. F.;
Balcells Terés, Joaquim;
Cebrián, J. A.;
Martin-Orúe, S. M.;
.
(1998)
.
Excretion of endogenous and exogenous purine derivatives in sheep: effect of increased concentrate intake.
British Journal of Nutrition, 1998, vol. 79, p. 237-240.
https://doi.org/10.1079/BJN19980040.
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The present study examined the endogenous urinary excretion of purine derivatives (PD;
allantoin, uric acid and xanthine plus hypoxanthine) in fed animals. Four Rasa Aragonesa ewes
fitted with simple cannulas in the rumen and proximal duodenum were used. Animals were
given a lucerne (Medicago sativa) hay diet, as sole feed (A) or supplemented, respectively, with
220 (B), 400 (C), and 550 (D) g rolled barley grain/d following a 4 x 4 random factorial design.
Duodenal flow of purine bases (PB) was determined by the dual-phase marker system. 15N was
infused continuously into the rumen to label exogenous or microbial PB. Duodenal PB flow and
urinary excretion of PD increased with digestible organic matter intake showing a constant
recovery of duodenal PB. The isotope dilution of PD in urine samples confirmed the presence of
an endogenous fraction, originating from tissues, that increased from 115.2 (SE 5.84) pmol/kg
@ 75 for the basal diet to 304.2 (SE 7.6) pmol/kg @'75 at the highest level of duodenal PB.